'Sound words' are onomatopoeia
Alliteration is a sentence or phrase with all the words starting with the same letter. EX: Peter Piper Picked A Pickled Pepper. (almost all in this case)
Simile: A comparison using like or as - EX: "As soft as a baby's bottom"
Imagery: Connotative (words that stick out) used to paint a picture in the reader's mind - EX: "I stared at the window, watching each raindrop race to the bottom, one by one." VS "It was raining outside"
